Measuring mass with a triple-beam balance

Written By India Gate on Friday, May 27, 2011 | 1:51 AM

The triple-beam balance was once the "standard" balance in the general chemistry lab. While the electronic balance has replaced it in many cases, good science students should be familiar with the triple-beam balance and how to read one. a triple-beam balance The balance is named for its three "beams". An object is placed on the pan of the balance and tares on the beams are moved to balance the mass. As you face the balance, the back beam is graduated in 10 gram steps and the middle beam is graduated in 100 gram steps. It is very important that the tares on these two beams are in the notch for the whole number of grams and not in between notches. The front beam is a sliding scale graduated in grams. The tare on this beam can be positioned anywhere on the scale. Masses on a triple-beam balance can be read to tenths of a gram, and estimated to hundredths. Clicking on the balance picture will give you a close view of the position of the tares on the three beams. What mass is represented, to five significant digits?